class Solution {
public:
    TreeNode* pruneTree(TreeNode* root) {
		if(root == nullptr)
        	return nullptr;
            
        root->left = pruneTree(root->left);
        root->right = pruneTree(root->right);
        
        if (root->left == nullptr && root->right == nullptr && root->val == 0)
        	return nullptr;
        else
        	return root;    
        
        return nullptr;
    }
};